Speedo drive AGAIN

[dapper]

Check the diameter of the wheel drive. IIRC the steel one I got from Sundar scoots was narrower than a nylon one I had, so didn't fit it but used the steel worm with a nylon wheel drive which worked for me.

[vRSG60]

Thanks for the tip. I'm not at home tonigsanyo can't check. I looked at the drive gear and it looked quite worn with metal shavings in the grease. It seems to be critical where the gear is positioned on the hub to get maximum contact with the worm.

[vRSG60]

After much buggering about and assembly dis-assembly, I finally got mine to work, for a week. Now it runs about 10MPH slow.
I think the casting bore the worm sits in is worn (I've tried everything else). I guess it needs boring out and a bush putting in.
Failing that I'm stumped.

[gaz_powell]

there are two types of speedo drive pinnions - for drum hub and for original disc hub

the one for the disc brake has a thicker end - where it sits into the backplate

have a look at the drum and disc picture on SR website -

drum http://www.scooterrestorations.com/lamb ... ion-nylon/

disc http://www.scooterrestorations.com/lamb ... ion-nylon/

there is a definate difference in the pictures

i recently built an orginal disc and just put in a regular pinnion and it worked but wasnt smooth and it was very slow + it didnt clock the correct miles up on the trip - so i`ve jsut sent off for the disc one to see how that performs

i recently spent a morning working on a all metal one on a ScootRS disc - took hub off and worked it with grinding paste gentle moving back and forward until it could be spun in both directions with no problem - reassembled it and it worked lovely nice and smooth down to the test centre and back so no idea how accurate it is !!- will wang it at the weekend to Blazing Glory do at Notts

fingers crossed it lasts the distance

gaz

[vRSG60]

I have a drum brake model and am fitting drum model drives. Mine's stopped working again. I'm fed up to the back teeth of this. Even when new the worm and gear don't seem to engage properly.

[vRSG60]

I've ordered ANOTHER metal worm and gear. I'm a bit reluctant to just fit this one. I really need to have a good look at the assembly and try to sort out why they only last a few miles.

[gaz_powell]

so having ruled out the disk/drum difference and its not a scootrs/sterling/spaq disc try these few things :-

based on my recent experience

1. put the drive and bush in the backing plate and tighten it up as you would normally when the hub is assembled - this will allow you to check if the drive is free when the assembly is bolted up - when I did this I noticed that the drive was locking solid - I put a small washer in to space the drive and a further washer on the bush to backplate so I could tighten the assembly but still allow the drive to move free

2. tap the ring on but not fully home and assemble the hub - look into the hub through the hole where the drive bush screws into the backplate and see where it lies - try the drive and see what happens - I had one that if the ring was tapped fully home it kept shredding the drives - keep trialling until if necessary it is fully home.

3. when your happy with the above add some grind paste to the ring and drive and work it backwards and forward until it runs smooth - clean it all so no paste left then grease the whole assembly

best of luck

ps just fitted a spaq pepperpot with metal drive for a mate and it worked perfect straight away - lovely and smooth (only been round the block twice mind) always the same when you do a job for someone else - I`m sick of messing about with mine!!

[vRSG60]

Thanks Gaz. I've had my suspicions about the position of the gear drive on the hub too.
Why is there a hole in the gear drive?

[gaz_powell]

not sure about the hole in the ring but have always wondered - they are on plastic and metal type

[vRSG60]

All assembled now.

1. Drive seems to run free. The only washers I have with the correct bore are the same outer diameter as the worm, so I'm loathe to fit them because the washer may catch on the gear drive.

2. If the ring isn't fully positioned on the hub the backplate seems to sit against the speedo drive and not the bearing bush. Also looking down the hole the gear drive didn't seem to be central. I ended up fitting the gear drive about 2mm down from the edge of the hub.

3. No grinding paste to hand yet. I'll get some and them trial the whole assembly.

I know I'm going to have to bite the bullet at some time and give it a proper trial but on past occasions all seemed well and then 10 - 20 miles later bugger all.